HI. I am new here. 

My husband and I have been married almost 7 years. I have a very close relationship with my youngest son (18) and my husband has no tolerance for my son. He is a great kid, great future ahead of him, no trouble, follows all rules and keeps his mouth shut. My husband picks at everything he does and never talks to him unless he is "barking orders".

Is this jealousy? Why would he act this way? 

His children are grown and gone.. 26 and 24. They never really lived with him. They lived with their mother most of the time.